KR20090019505A - Apparatus and method for sychronization of gsm neighbor cell in mobile communication system - Google Patents

Abstract

An apparatus and a method for synchronization of GSM neighbor cell in mobile communication system are provided to obtain the synchronization of the cell of the heterogeneous network like GSM detecting the synchronous burst in the calculated electrical transmission gap. A terminal(400) of an asynchronous 3G mobile communications systems comprises a controller(402), a memory(404), a communications unit(406), an electrical transmission gap confirmation device(408), a frequency extracting unit(410), an electrical transmission gap requester(412) and a motive extracting unit(414). A base station(450) comprises a controller(452), a communications unit(454), an electrical transmission gap processing unit(456) and a gap request receiving part(458). The communications unit receives the frequency burst and synchronous burst and transmits the request of the electrical transmission gap.

Description

Apparatus and method for synchronizing cells of adjacent mobile communication globalization system in mobile communication system {APPARATUS AND METHOD FOR SYCHRONIZATION OF GSM NEIGHBOR CELL IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to an apparatus and method for synchronizing a cell of a neighboring Global System for Mobile Communications (GSM) in a mobile communication system. In particular, the present invention relates to acquiring synchronization of an adjacent GSM cell during traffic transmission in a 3G mobile communication system. An apparatus and method are provided.

In the environment where 3G mobile communication system and GSM coexist, when 3G mobile communication system is a serving cell, in order to prepare for handover to GSM system, synchronization of neighboring GSM cells should be acquired in advance. Synchronous acquisition of adjacent GSM cells consists of two stages: frequency burst (FB) search and synchronization burst (SB) detection. The first step, FB search, locates the FB on the Broadcast Control Channel (BCCH) carrier of the adjacent GSM cell, which finds the approximate frame boundary of the GSM system and offsets the frequency. )). The second step, SB detection, detects the SB located one frame behind the FB in the BCCH carrier of the adjacent GSM cell. Through this, the SB detection finds the correct frame boundary and acquires synchronization by reading the frame number. The neighboring GSM cell, which has been once synchronized, then performs only SB detection periodically to maintain synchronization to prepare for handover.

1 is a diagram illustrating a structure of a control channel transmitted on a BCCH carrier of an adjacent GSM cell according to the prior art. Referring to FIG. 1, a control channel includes an FCCH (Frequency Correction Channel) frame denoted by F, a Synchronization Channel (SCH) frame denoted by S, a Broadcast Control Channel (BCCH) frame, and a common control channel (CCCH). Common Control Channel) frame, and Idle frame indicated by I. At this time, the FB and SB of GSM are contained in time slot 0 from among the frames of the FCH indicated by F of 51-multiframe and the SCH indicated by S, respectively.

If the 3G mobile communication system continuously searches 11 frame sections in idle state, which is not communicating, it can succeed in finding at least one FB, and then acquire synchronization by detecting SBs after 1 frame. Can be. However, when the 3G mobile communication system is in a traffic data transmission state, since the traffic data is transmitted and received in all sections, a 3G mobile communication system should be used to obtain synchronization of adjacent GSM cells. In the asynchronous 3G mobile communication system, a compressed mode is defined to be used for power measurement, synchronization acquisition, and maintenance of adjacent GSM cells in a transmission gap (hereinafter, referred to as 'TG').

In case of synchronous acquisition or maintenance using TG in asynchronous 3G mobile communication system, since 11 frames of TG cannot be made continuously, TG of a certain length is repeatedly made at a specific period. TGPS '). Such TGPS has several patterns depending on the length of the TG and the period of the TG. The base station of an asynchronous 3G mobile communication system must acquire and maintain synchronization for the top 6 cells of high power in the list of neighboring GSM cells.When a GSM cell to acquire synchronization or check synchronization status is generated, the TGPS is transmitted to the terminal. Assign. When the base station allocates the TGPS to the terminal, it transmits the starting frame position of the TG, the purpose of the TG, the length of the TG, the period of the TG, and the state of the TG through a layer control channel. [Reference Specifications: 3GPP TS 25.331, 10.3.6.33 ~ 34] When the base station assigns a specific TGPS to the terminal, the terminal performs FB search and SB detection of each neighboring GSM cell using the specific TGPS to synchronize the neighboring GSM cells. Acquire and maintain When the terminal completes the synchronization acquisition of the GSM cell, the result of the synchronization acquisition is transmitted to the base station through the upper layer control channel, and the base station notifies the terminal that TGS has been completed through the TG state information of the upper layer control channel. However, making a TG in an asynchronous 3G mobile communication system causes a drop in the transmission rate of traffic data. Therefore, it is desirable to minimize TG.

2 is a view comparing a frame of an asynchronous 3G mobile communication system and a frame of a GSM system according to the prior art. Referring to FIG. 2, it can be seen that the frame of the asynchronous 3G mobile communication system and the frame of the GSM system are different from each other in the size of the frame and the size of the timeslot. Therefore, even if the 3G mobile communication system generates intervals of a certain period and length for synchronization acquisition and maintenance of adjacent GSM cells during traffic data transmission, it takes more time to acquire and maintain synchronization.

When transmitting traffic data in the GSM system, an idle frame is used to acquire neighboring GSM cells, and the FB can be found in up to 11 idle frames. SB detection is possible in the second idle frame after finding the FB. In this case, the idle frame of the traffic channel is opened in a region where the sections of the GSM control channel with FB and SB do not overlap each other, so that fast synchronization can be obtained. However, the intervals provided for synchronization acquisition and maintenance of adjacent GSM cells in the 3G mobile communication system are not synchronized with the GSM control channel, so that different intervals overlap each other, so that it takes longer to find an FB and detect an SB. It is necessary. The longer and longer the interval, the lower the transmission performance of the traffic data.

3 is a diagram illustrating a synchronization acquisition process of adjacent GSM cells during traffic transmission in an asynchronous 3G mobile communication system according to the prior art. Referring to FIG. 3, when a base station allocates a specific TGPS to acquire adjacent GSM cells during traffic transmission in an asynchronous 3G mobile communication system, the terminal generates a TGPS from a designated frame and starts searching for the FB of the GSM control channel. Whenever TG occurs with the period and length defined in TPGS, FB search is performed.If FB succeeds in finding FB from TG completely inside TG, after FB is found, FB stops searching and starts SB detection. SB detects by waiting until the incoming TG completely. When the SB is detected, the base station is informed that synchronization has been acquired, the SB detection is stopped, and when the base station notifies the terminal of the end of the TGPS, the generation of the TGPS is stopped. If SB detection fails, the asynchronous 3G mobile communication system continues to generate TGPS of TGPS until the SB succeeds.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and method for synchronizing cells of heterogeneous networks such as GSM in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for acquiring synchronization of a cell of a heterogeneous network such as an adjacent GSM when transmitting traffic in a mobile communication system.

It is still another object of the present invention to search for a frequency burst in a transmission gap period when transmitting traffic in a mobile communication system, and calculate a transmission gap period for detecting a synchronization burst to detect a synchronization burst in a calculated transmission gap to detect a heterogeneous network such as an adjacent GSM. An apparatus and method for acquiring synchronization of a cell are provided.

According to a first aspect of the present invention for achieving the above objects, the terminal of the third generation mobile communication system to acquire the synchronization of the adjacent mobile communication globalization system cells, the frequency burst (Synchronization Burst) and the synchronization burst (Synchronization Burst) A communication unit for receiving a transmission gap request and transmitting a transmission gap request, a transmission gap checking unit for checking a predetermined transmission gap section in a traffic section, and a mobile communication globalization system (GSM: Global System for Mobile) adjacent to the transmission gap section. A frequency extraction unit for searching and extracting a frequency burst of a cell; and calculating the next transmission gap interval when the frequency burst is extracted, and transmitting the transmission gap request message having information about the calculated transmission gap through the communication unit. A transmission gap request unit for controlling transmission to a base station; And a synchronization extractor for extracting the synchronization burst during the interval.

According to a second aspect of the present invention for achieving the above objects, the base station of the third generation mobile communication system for adjusting the transmission gap, the communication unit for transmitting or receiving traffic data and receiving a transmission gap request message from the terminal; Receiving the transmission gap request message through the communication unit, the gap request receiving unit for calculating the next transmission gap (transmission gap) interval, and limiting the traffic interval according to the transmission gap calculated by the gap request receiving unit to calculate the calculated transmission gap It characterized in that it comprises a transmission gap processing unit for generating.

According to a third aspect of the present invention for achieving the above objects, a method of obtaining synchronization of a cell of an adjacent mobile communication globalization system in a terminal of a third generation mobile communication system includes a predetermined transmission gap in a traffic interval. A step of identifying a section, searching for and extracting a frequency burst of a neighboring Global System for Mobile Communications (GSM) cell during the transmission gap section, and calculating a next transmission gap section when the frequency burst is extracted. And transmitting the transmission gap request message having information on the calculated transmission gap to a base station, and extracting the synchronization burst during the calculated transmission gap period to obtain synchronization. It is done.

According to a fourth aspect of the present invention for achieving the above objects, a method for adjusting a transmission gap in a base station of a third generation mobile communication system, the traffic through the communication unit from the terminal in the traffic period for transmitting or receiving traffic data; And receiving a transmission gap request message, calculating a next transmission gap section, and generating a calculated transmission gap by limiting a traffic section according to the calculated transmission gap.

As described above, the present invention provides a communication unit for receiving a frequency burst and a synchronization burst and transmitting a transmission gap request, and confirming a transmission gap for checking a predetermined transmission gap section in a traffic section. And a frequency extractor for searching and extracting frequency bursts of adjacent Global System for Mobile Communications (GSM) cells during the transmission gap period, and calculating the next transmission gap period when the frequency burst is extracted. A transmission gap request unit controlling to transmit the transmission gap request message having the calculated transmission gap information to the base station through the communication, and a synchronization extracting unit extracting the synchronization burst during the calculated transmission gap period; Three adjacent mobile communication systems in a mobile communication system The present invention relates to an apparatus and method for synchronizing cells in a computerization system, and has an effect of improving the transmission performance of traffic data by adjusting the frequency and length of transmission gap intervals.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. If it is determined that the gist of the present invention may be unnecessarily obscured, detailed description thereof will be omitted.

The present invention relates to an apparatus and method for acquiring synchronization of a cell of a heterogeneous network such as an adjacent GSM when transmitting traffic in a mobile communication system. Hereinafter, the apparatus of the present invention will be described with reference to FIG.

FIG. 4 is a diagram illustrating a configuration of a mobile communication system for acquiring synchronization of cells of heterogeneous networks such as neighboring GSM during traffic transmission according to an embodiment of the present invention. Referring to FIG. 4, the terminal 400 of the asynchronous 3G mobile communication system includes a control unit 402, a memory 404, a communication unit 406, a transmission gap check unit 408, a frequency extractor 410, and a transmission gap request. And a synchronization extractor 414. The base station 450 includes a controller 452, a communication unit 454, a transmission gap processing unit 456, and a gap request receiving unit 458. Configure.

First, referring to the components of the terminal 400, the memory 404 of the terminal 400 includes a program for controlling the overall operation of the terminal 400, an application program, and storage data (phone number). , An SMS message, a compressed image file, a video, etc.) and a period of a predetermined transmission gap received from the base station 450.

The communication unit 406 of the terminal 400 performs a function of despreading and channel decoding a received signal by decreasing a frequency of a radio frequency signal received through an antenna and transmitting the received signal. When data is channel coded and spreaded, the frequency is raised and transmitted through an antenna, and under the control of the control unit 402 in a transmission gap (hereinafter, referred to as TG). A frequency burst (hereinafter referred to as 'FB') and a synchronization burst (hereinafter referred to as 'SB') are received.

The transmission gap checking unit 408 of the terminal 400 checks the transmission gap preset by the base station 450 and confirms the start and end of the transmission gap section in the traffic section. When the frequency extractor 410 of the terminal 400 confirms the transmission gap section through the transmission gap check unit 408, the frequency extractor 410 detects a frequency burst by searching for a frequency burst of an adjacent GSM cell during the transmission gap section.

When the frequency extractor 410 detects a frequency burst, the transmission gap request unit 412 of the terminal 400 calculates a time for detecting a synchronization burst and determines an appropriate transmission gap period for detecting a synchronization burst. Request to the base station 450. The transmission gap request information transmitted to the base station 450 is a frame and slot number of the mobile communication system to generate a transmission gap, and if necessary, also transmits a length of the transmission gap. The frame and slot numbers can be calculated by estimating the time at which the synchronization burst is to be located in the mobile communication system based on the position of the frequency burst of a cell of a heterogeneous network such as an adjacent GSM. The length of the transmission gap is set in consideration of the length of the synchronization burst from the start time of the transmission gap, the hardware preparation time for receiving the synchronization burst, and the hardware preparation time for receiving traffic after the transmission gap ends. The transmission gap request information may be transmitted in addition to a control channel that is in charge of a measurement report of existing neighbor cells and serving cells.

The synchronization extractor 414 of the terminal 400 searches for and extracts a synchronization burst of an adjacent GSM cell in the calculated transmission gap interval calculated by the transmission gap request unit 412 to obtain synchronization.

The controller 402 controls the transmission gap check unit 408, the frequency extractor 410, the transmission gap request unit 412, and the synchronization extractor 414. That is, the control unit 402 may perform the functions of the transmission gap checking unit 408, the frequency extracting unit 410, the transmission gap requesting unit 412, and the synchronization extracting unit 414. In the present invention, it is shown to configure them separately to explain each function separately. Therefore, in the case of actually implementing a product, all of them may be configured to be processed by the controller 402, and only some of them may be configured to be processed by the controller 402.

Next, referring to the components of the base station 450, the communication unit 454 of the base station 450 despreads and receives a received signal by decreasing the frequency of a radio frequency signal received through an antenna when receiving. It performs a function of decoding (channel decoding), and when transmitting, data is channel coded (spread) and spread (spreading), the frequency is increased and transmitted through the antenna, and in accordance with the present invention, the terminal ( 400, a request for a transmission gap is received.

When the gap request receiving unit 458 of the base station 450 receives the transmission gap request from the terminal 400, the gap request receiving unit 458 calculates a request transmission gap period and provides the calculated transmission gap period to the transmission gap processing unit 456. do.

The transmission gap processing unit 456 of the base station 450 presets the transmission gap period of the terminal 400 to provide the terminal 400 to the terminal 400, and controls to limit the transmission of traffic data in the transmission gap period. When receiving the calculated transmission gap period requested by the terminal 400 from the gap request receiving unit 458, it controls to limit the transmission of traffic data in the calculated transmission gap period.

The controller 452 controls the transmission gap processor 456 and the gap request receiver 458. That is, the controller 452 may perform the functions of the transmission gap processing unit 456 and the gap request receiving unit 458. In the present invention, it is shown to configure them separately to explain each function separately. Therefore, in the case of actually implementing a product, all of them may be configured to be processed by the controller 452, and only some of them may be configured to be processed by the controller 452.

7 is a diagram illustrating a synchronization acquisition process of a cell of a heterogeneous network such as a neighboring GSM during traffic transmission in a mobile communication system according to an embodiment of the present invention. Referring to FIG. 7, when a base station allocates a specific TGPS to acquire cell synchronization of a heterogeneous network such as a neighboring GSM during traffic transmission of a mobile communication system, the terminal generates a TGPS from a designated frame and starts searching for an FB of a GSM control channel. . Whenever TG occurs with the period and length defined in TPGS, FB search is performed.If FB succeeds in finding FB in TG completely inside TG, after FB is found, FB search stops and SB detection starts. As described above, the SB is detected and SB is detected by using the calculated TG generated at a position necessary for detecting the SB and having a length necessary to detect the SB. Thus, the generation of TG wasted without detecting SB.

Hereinafter, a method of acquiring synchronization of a cell of a heterogeneous network such as a neighboring GSM during traffic transmission in a mobile communication system according to the present invention configured as described above will be described with reference to the accompanying drawings.

FIG. 5 is a flowchart illustrating a process of acquiring synchronization of cells of heterogeneous networks such as GSM adjacent in a traffic period in a terminal of a mobile communication system according to an exemplary embodiment of the present invention. Referring to FIG. 5, the terminal 400 according to the present invention proceeds to step 502 of the traffic section in which the traffic data is transmitted or received in step 500, and confirms whether or not the transmission gap section starts. Return to step to perform the traffic section.

In step 502, when detecting the start of the transmission gap section, the terminal 400 proceeds to step 504 to search for frequency bursts of adjacent GSM cells during the transmission gap section, and proceeds to step 506 to search for a transmission gap section. Result Check whether a frequency burst has been detected. If it is confirmed that no frequency burst is detected, the process returns to step 500 to perform the traffic section.

When the frequency burst of the adjacent GSM cell is detected in step 506, the terminal 400 proceeds to step 508, calculates a transmission gap interval for the synchronization burst detection, and proceeds to step 510 to control the base station 450. Request the transmission gap calculated through the channel, proceed to step 512 performs a traffic interval for transmitting or receiving traffic data, and proceeds to step 514 to check whether the calculated transmission gap interval starts. If it is not the start of the calculated transmission gap section, the process returns to step 512 to perform the traffic section.

Upon detecting the start of the calculated transmission gap section as a result of checking in step 514, the terminal 400 proceeds to step 516 and searches for a synchronization burst of a cell of a heterogeneous network such as a neighboring GSM during the calculated transmission gap section. In step 518, it is checked whether the search result synchronization burst of the calculated transmission gap section is detected. If it is determined that the synchronization burst has not been detected, the process returns to step 512 to perform a traffic section for transmitting or receiving traffic data, and then repeats the process.

If it is determined in step 518 that the synchronization burst of a cell of a heterogeneous network such as an adjacent GSM is detected, the terminal 400 acquires synchronization and terminates the algorithm of the present invention.

6 is a flowchart illustrating a process of providing a transmission gap requested by a base station of a mobile communication system according to an exemplary embodiment of the present invention. Referring to FIG. 6, the base station 450 according to the present invention proceeds to step 602 of a traffic section in which the traffic data is transmitted or received in step 600, and checks whether a request for transmission gap through the control channel is received from the terminal 400. In step 604, when receiving the request for transmission gap, the process proceeds to step 604 to determine whether the transmission gap interval calculated according to the transmission gap request starts. The traffic is stopped during the calculated transmission gap interval requested, and then the process returns to step 600 again.

If there is no transmission gap request as a result of checking in step 602, the base station 450 proceeds to step 608 to check whether a transmission gap section occurs according to a preset period, and if it is determined that the transmission gap section has not occurred, Returning to step 600, the traffic section is performed.

If it is determined in step 608 that the start of the transmission gap section of the predetermined period is detected, the base station 450 proceeds to step 610 to stop the traffic during the transmission gap section of the preset period, and then back to step 600 Go back.

Meanwhile, although the embodiment of the present invention describes frequency acquisition and synchronization acquisition between a mobile communication system, in particular, an asynchronous system and a GSM system, it can be applied to other systems having the above-mentioned characteristics, for example, OFDM and OFDMA schemes. It is self-evident.

In other words, there may be many other ways in which the invention may be practiced without departing from the scope of the following claims.

1 illustrates a structure of a control channel transmitted on a BCCH carrier of an adjacent GSM cell according to the prior art;

2 is a view comparing a frame of an asynchronous mobile communication system and a frame of a GSM system according to the prior art;

3 is a diagram illustrating a synchronization acquisition process of an adjacent GSM cell during traffic transmission in an asynchronous mobile communication system according to the prior art;

4 is a diagram illustrating a configuration of an asynchronous mobile communication system for acquiring synchronization of adjacent GSM cells during traffic transmission according to an embodiment of the present invention;

5 is a flowchart illustrating a process of acquiring synchronization of an adjacent GSM cell in a traffic period in a terminal of an asynchronous mobile communication system according to an embodiment of the present invention;

6 is a flowchart illustrating a process of providing a transmission gap requested by a base station of an asynchronous mobile communication system according to an embodiment of the present invention;

7 is a diagram illustrating a synchronization acquisition process of a neighboring GSM cell during traffic transmission in an asynchronous mobile communication system according to an embodiment of the present invention.

Claims (22)

A terminal of a mobile communication system for acquiring synchronization of adjacent mobile communication globalization system cells, A communication unit for receiving a frequency burst and a synchronization burst and transmitting a transmission gap request; A transmission gap checking unit for checking a predetermined transmission gap section in the traffic section; A frequency extracting unit for searching and extracting frequency bursts of cells of adjacent heterogeneous networks during the transmission gap period; A transmission gap request unit which calculates a next transmission gap period when the frequency burst is extracted and controls to transmit the transmission gap request message having information about the calculated transmission gap to the base station through the communication unit; And a synchronization extractor for extracting the synchronization burst during the transmission gap period. The method of claim 1, The transmission gap request unit, And when the frequency burst is extracted, a transmission gap section from which a synchronization burst can be extracted is calculated as a next transmission gap section. The method of claim 1, The transmission gap request unit, And control the transmission gap request message to be transmitted to the base station through a control channel. The method of claim 1, The transmission gap request message, And a terminal for generating a next transmission gap and information about the slot number. The method of claim 4, wherein The transmission gap request message, And a terminal containing information about the length of the next transmission gap. The method of claim 5, The length of the transmission gap is, And a length of the synchronization burst, a hardware preparation time for receiving the synchronization burst, and a hardware preparation time for receiving traffic after the transmission gap is over. In the base station of the mobile communication system for adjusting the transmission gap, A communication unit for transmitting or receiving traffic data and receiving a transmission gap request message; A gap request receiving unit for calculating a next transmission gap section when receiving the transmission gap request message from the terminal through the communication unit; And a transmission gap processing unit for generating the calculated transmission gap by limiting the traffic interval according to the transmission gap calculated by the gap request receiving unit. The method of claim 7, wherein The transmission gap request message, The base station characterized in that receiving from the terminal via a control channel (control channel). The method of claim 7, wherein The transmission gap request message, A base station comprising information on a frame and a slot number to generate a next transmission gap. The method of claim 9, The transmission gap request message, A base station comprising information about the length of the next transmission gap. The method of claim 10, The length of the transmission gap is, A length of a synchronization burst, a hardware preparation time for the terminal to receive the synchronization burst, and a hardware preparation time for receiving the traffic after the transmission gap ends. A method for acquiring synchronization of cells of an adjacent mobile communication globalization system in a terminal of a mobile communication system, Checking a predetermined transmission gap in the traffic section; Searching and extracting frequency bursts of adjacent Global System for Mobile Communications (GSM) cells during the transmission gap; Extracting the frequency burst, calculating the next transmission gap interval, Transmitting the transmission gap request message having information on the calculated transmission gap to a base station; And obtaining synchronization by extracting the synchronization burst during the calculated transmission gap period. The method of claim 12, The process of calculating the next transmission gap interval, And if the frequency burst is extracted, a transmission gap section from which a synchronization burst can be extracted is calculated as a next transmission gap section. The method of claim 12, The step of transmitting the transmission gap request message to the base station, And transmitting the transmission gap request message to the base station through a control channel. The method of claim 12, The transmission gap request message, And information about the frame and the slot number to generate the next transmission gap. The method of claim 15, The transmission gap request message, And obtaining information about the length of the next transmission gap. The method of claim 16, The length of the transmission gap is, Length of the synchronization burst, hardware preparation time for receiving the synchronization burst, and hardware preparation time for receiving traffic after the transmission gap is over. In the method for adjusting the transmission gap in the base station of the mobile communication system, Calculating a next transmission gap section when the transmission gap request message is received from the terminal through the communication unit in a traffic section for transmitting or receiving traffic data; And limiting the traffic interval according to the calculated transmission gap to generate the calculated transmission gap. The method of claim 18, The transmission gap request message, A method for adjusting a transmission gap, characterized in that received from the terminal via a control channel. The method of claim 18, The transmission gap request message, A method of controlling a transmission gap, comprising information about the frame and slot number at which the next transmission gap should be generated. The method of claim 20, The transmission gap request message, A method for adjusting the transmission gap, characterized in that it comprises information about the length of the next transmission gap. The method of claim 21, The length of the transmission gap is, A length of a synchronization burst, a hardware preparation time for the terminal to receive the synchronization burst, and a hardware preparation time for receiving the traffic after the transmission gap ends. How to.

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